Install liblzma-dev to fix CI

Symptom was:
> Could NOT find LibLZMA (missing: LIBLZMA_LIBRARY LIBLZMA_INCLUDE_DIR
> LIBLZMA_HAS_AUTO_DECODER LIBLZMA_HAS_EASY_ENCODER LIBLZMA_HAS_LZMA_PRESET)

Signed-off-by: Sebastian Pipping <[email protected]>

Author: hartwork

.github/workflows/cmake-multi-platform.yml

@@ -35,7 +35,7 @@ jobs:
     - uses: actions/checkout@v3
 
     - name: Install Ninja
-      run: sudo apt install -y ninja-build
+      run: sudo apt install -y liblzma-dev ninja-build
 
     - name: Set reusable strings
       # Turn repeated input strings (such as the build output directory) into step outputs. These step outputs can be used throughout the workflow file.